package day_2022_7_to_8.day48;

/**
 * @author haomin
 * @date 2022/08/28 00:10
 **/
public class Day42_2_Num96_NumTrees {
    class Solution {
        public int numTrees(int n) {
            int[] dp = new int[n+1];
            dp[0] = dp[1] = 1;
            for(int i = 2; i <= n; ++i){
                for(int j = 1; j <= i; ++j){
                    dp[i] += dp[j-1] * dp[i-j];
                }
            }
            return dp[n];
        }
    }
}